Facies characteristics and paleoenvironments of the Maastrichtian-Paleocene succession in Gabal Ras Al-Giffa and Gabal Bir Umm Said, west-central Sinai and a comparison with some sections from the northern and southern Sinai, Egypt

The Maastrichtian-Paleocene succession at Gabal Ras Al-Giffa and Gabal Bir Umm Said (west-central Sinai) consists of monotonous argillaceous chalky limestone and mudrocks. Planktonic and benthonic foraminifera as well as calcareous nannofossils are the most abundant fossils. An unconformity at the K/Pg boundary is detected on paleontological basis. The limestones are dominated by lime-mudstone, foraminiferal wackestone and foraminiferal wackestone/packstone. Lithofacies characters, faunal content and microfacies interpretation indicate that the Maastrichtian-Paleocene succession has been deposited in a low-energy, open-marine environment oscillating from middle to outer shelf under tropical to subtropical conditions. Deposition took place below the effective wave base probably at water depths varying between 50 and 200 meters. A marked overall rise in sea level starting in the early Maastrichtian and continuing throughout the Paleocene was interrupted by short periods of sea level fall. Lithofacies distribution and depositional patterns indicate that sedimentation was mainly controlled with changing intensities by transgressions, terrigenous input and tectonic patterns (basin subsidence and inversion).